Functional and morphological basics of early brain development

Cerebral perfusion and metabolism increase in a non-linear manner before and after birth. Their development mainly depends on the growth of the brain (100g in week 25 of gestation, 350g at term, 1000g at 18 months, and 1400g at 15 years of age) and the synaptogenesis (varying in different regions of the brain; e.g., in the visual cortex: slow increase before birth, “spurt“ during the first 4 months, maximum at 12 months, selective stabilisation and 40% elimination up to the age of 11 years). Regional cortical maturation is reflected by the progress of myelination, as well as by the increase of perfusion and metabolism, which can be depicted by MRI, SPECT, and PET, respectively.

The radionuclide methods cannot be used for the measurement of cerebral blood flow (CBF) in healthy children. We are now able to show the normal development of global CBF volume by using duplex volumetry of the brain-feeding extracranial arteries, a non-invasive ultrasound method. CBF volume increases from 30ml/min [equivalent to a CBF of 15ml/100g/min] at 32 weeks of gestation up to 75ml/min [18ml/100g/min] at term, reaches a maximum of ~ 900ml/min [75ml/100g/min] at the age of 6 years, and decreases to the adult level of 700ml/min [50ml/100g/min] at the age of 15 years. The relationship between morphology and function of the brain now can be described more in detail by using new techniques.